"19 Down..." � When a new murder leads to a connection with an infamous serial killer, Grissom secretly joins the class of well-known criminal pathologist Dr. Raymond Langston (Fishburne), to gain access to the killer and get a crack in the case, on CSI: CRIME SCENE INVESTIGATION, Thursday, Dec. 11 (9:00-10:00 PM, ET/PT) on the CBS Television Network.